HOW DO WE RESPOND TO

CHALLENGES CAUSED BY EARTH’S FORCES?

epicentre the point on Earth’s surface directly above the location of an earthquake

Ring of Fire

Pacific plate

Shanghai

Kolkata

Mumbai

Los AngelesTokyo

Nagoya

KobeOsaka

Kyoto

Shenzhen

Delhi

Jakarta

Manila

Seoul

GuangzhouFoshan

Bangkok

NORTHAMERICA

SOUTHAMERICA

ASIA

AUSTRALIA

volcanoes

largest earthquakes since 1900

urban areas with populations over 10 million

plate boundary0 3000 km1500

P A C I F I C O C E A N

I N D I A N

O C E A N

ATLANTIC

OCEAN

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Crowle Art Group

4th pass

Geography 7 SB

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Approved

Not Approved

FIGURE 1.18 This map shows the Ring of Fire region, around the Pacific Ocean. Within it, the map shows the largest earthquakes since 1900, volcanic eruptions, and urban areas with more than 10 million people as of 2013.

The forces that create landforms can also pose great dangers to people. Two such forces are volcanoes and earthquakes.

THE DANGERS OF EARTHQUAKESMost large earthquakes happen where plates are moving past or under each other. For example, where the edges of the Pacific plate meet the Eurasian, Australian, and American plates, they create the Ring of Fire. It is the earthquake zone and the string of volcanoes that surround the Pacific Ocean (Figure 1.18). Where plates meet, pressure builds and grows.

Ring of Fire

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When the energy is released, shock waves shake the land. The epicentre is the place on Earth’s surface directly above where the main shock occurs. After the first shock wave, there can be a series of smaller shock waves called aftershocks.

During an earthquake, Earth’s surface may shift by as much as several metres. In open areas, shock waves from earthquakes rarely injure anyone, but the force can destroy buildings (Figure 1.19). The falling debris often injures or kills people who are inside or nearby.

As well, the shaking of Earth’s surface may create many damaging natural events, such as tsunami waves. The 2004 earthquake in the Indian Ocean that you read about on page 14 is an example of this. Tsunamis can move at speeds of up to 800 km/h, which is about as fast as a passenger jet flies. They can travel for thousands of kilometres across open water. Depending on where and when they reach land, tsunamis can cause huge amounts of destruction, injury, and death.

THE DANGERS OF VOLCANOESThe flows of lava that escape during a volcanic eruption can be very harmful to people. However, because lava moves slowly, people usually have enough time to escape. The biggest risks to people from volcanoes are the very hot gases, ash, and rocks that are shot into the air during eruptions. These eruptions release toxic gases. These gases can make it hard to breathe, and they can damage people’s lungs.

The lava can cause fires, however, and the ash that is released can also destroy property. This can create huge challenges to local economies. It can even have worldwide effects.

epicentre the point on Earth’s surface directly above the location of an earthquake

FIGURE 1.19 This photo shows the scene after an earthquake in Beichuan County, in Sichuan, China, in 2008.

How would the earthquake have affected the people in my country?

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FOCUS ON

FORMULATE QUESTIONSWhen you are researching a geographic topic,

such as how mountains are formed or what effect

a landslide might have on a local community,

you need to ask good research questions. These

questions help you narrow your focus as well as

locate, gather, and organize your information.

A good inquiry question

• will lead to answers you don’t already know

• uses words whose meanings are clear

• is open-ended and will lead to many possible

answers

• helps give you answers that will focus your

research

• can be answered by gathering evidence

• might lead you to think about what you assumed

when you asked the question

• might lead you to ask more questions

A factual question, on the other hand, asks

for accurate details about a problem or topic, for

example, “What continent has the world’s tallest

mountain?” It is not a good inquiry question.

WHAT ARE GOOD INQUIRY QUESTIONS?When we study geography, key questions include

the following: What is where? Why there? Why

care? Look at the chart in Figure 1.20 for other

good examples.

TRY ITTry out your understanding of research questions.

1. Think about a geographic topic that you might

want to research. For example, you might want

to learn more about a recent natural disaster.

2. Decide what you want to learn about that

topic. Remember to think about the geographic

focus: What is where? Why there? Why care?

For example, perhaps you will decide to learn

the causes of the natural disaster, what could

have been done to prevent it, and whether

everyone acted properly to try to prevent it.

3. Write three possible research questions to help

you find out what you want to know. Ask one

or two classmates to review the questions and

offer suggestions for improvement. Revise your

questions, if necessary, based on their ideas.

Question Type Description Example

definitional asks to make the meanings of terms clear What exactly is a mountain?

comparative asks for differences between, or similarities in,

aspects of a problem or topic

How are the Rocky Mountains similar to the Alps?

cause and effect seeks reasons for the cause of a problem and an

understanding of its effects

Why are some mountains active volcanoes?

decision-making asks for decisions about actions that could help

solve a problem

What could be done to help protect people from

volcanic eruptions?

speculative suggests what conclusion might come from

an action

How many lives would be saved if people were

ordered to move away from volcanic mountains?

ethical examines the rights and wrongs of a problem

or topic

Should governments control how close people live

to active volcanoes?

FIGURE 1.20 This chart explains several types of questions.

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TOOLS FOR MEASURING DAMAGEThe seismograph is an important tool that measures and records the size and magnitude of movements of the ground, especially of an earthquake.Magnitude is determined by the strongest seismic waves that are recorded for an earthquake. As an example, the earthquake that caused the 2004 tsunami was a magnitude of 9.1. It was the third-largest earthquake ever recorded on a seismograph. Volcanic eruptions can also be measured on a seismograph. Before Mount Redoubt, Alaska, erupted in 2009 (Figure 1.21) scientists were able to issue warnings based on the data they recorded.

Scientists use a Richter scale to classify earthquakes. The difference between one whole number of magnitude and the next is a 10-times increase in energy. So, an earthquake of 6.0 releases 10 times more energy than an earthquake of 5.0 magnitude.

The damage to human-made structures, such as houses and roads (Figure 1.22), increases as the movements of the ground increase in size. For example, an earthquake that measures 4.0 to 4.9 on the Richter scale is considered small. In an earthquake of that size, windows might break and small objects fall from shelves. An earthquake that measures 7.0 to 7.9 is a major earthquake. This size earthquake causes buildings to be knocked off foundations and underground pipes to break.

seismograph a tool that measures and records the magnitude and duration of a disturbance of the ground, especially earthquakes

FIGURE 1.21 A scientist installs a seismic station near Mount Redoubt Volcano.

FIGURE 1.22 People carrying their belongings across a destroyed road in central Philippines after a 6.8 magnitude earthquake in February 2012

I wonder what kind of courses geologists take at school to have a career studying earthquakes?

I wonder whether there has ever been an earthquake in the Philippines before?

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HEROES IN ACTION

On January 12, 2010, a 7.0 magnitude

earthquake shook the Caribbean nation of

Haiti. The quake’s epicentre was just 25 km

from the capital city of Port-au-Prince.

The city was destroyed. Officials estimated

that 316 000 people died and 300 000

were injured. About 285 000 homes were

demolished or badly damaged.

Even before the earthquake, life was

difficult in Haiti. It was the poorest country in

the Americas. Half of the

population did not have

access to a toilet. Only

about one-third had safe

drinking water. For years,

Haiti struggled to keep a

stable government and a

working economy.

Unlike the state of

California in the United

States, which experiences

similar events, Haiti had

few resources to prepare

for earthquakes or other

natural disasters. Nor

did they have the resources to deal with the

devastation earthquakes can create.

HELP FOR HAITIFollowing the earthquake, international

aid agencies such as the Red Cross raced

to set up operations in Port-au-Prince.

Individuals hurried to help as well. Among

them was 13-year-old Bilaal Rajan from

Toronto, Ontario (Figure 1.23).

It wasn’t the first time Rajan had taken

action for Haiti. In 2004, a hurricane hit the

island. Rajan, then eight, spearheaded a

cookie-selling fundraiser at his school. He

and his team of 12 raised more than $6000

for UNICEF to help the people of Haiti.

Over the years, Rajan continued to

speak out for those suffering from natural

disasters and poverty. For example, as you

read about on page 14, in 2004, a huge

tsunami in the Indian Ocean caused great

devastation, as well as many injuries and

deaths. Rajan helped raise funds to help

the survivors through his Canada Kids

Earthquake Challenge. In 2005, he became

UNICEF Canada’s child ambassador. In 2010,

at the age of 13, he challenged

every Canadian child to raise

$100 for UNICEF Canada’s

Haiti Emergency Fund by

fundraising in their schools or

communities.

“The challenges of the

Haitian people won’t go

away overnight, but young

Canadians can make an

enormous difference,”

said Rajan.

Why did Rajan feel he

needed to get involved in this

crisis? “I know it’s hard to put

ourselves in other people’s shoes,” he said,

“but we have to. It’s our duty to help other

kids because, as Canadians, we have so

much and others don’t.”

A CALL TO ACTION 1. List several reasons why you think

people get involved in helping relief

organizations. Share your list with a

classmate and see if you can add more

reasons to your list. Decide which of

the reasons would most encourage

you to help a relief organization.

2. How will you contribute to an issue

you care about? What can be done in

your school community to fund raise

for this cause?

BILAAL RAJAN: HELPING VICTIMS OF HAITI’S EARTHQUAKE

FIGURE 1.23 Bilaal Rajan

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1. GEOGRAPHIC PERSPECTIVE Should people be

forced to move away from areas where there

are earthquakes and volcanoes? Consider the

impacts this policy would have. Create a t-chart

that lists pros and cons of such a policy. Express

your conclusion in a paragraph or by creating

a poster.

2. PATTERNS AND TRENDS Why do you think some

places have earthquakes, tsunamis, and

volcanoes while other places do not? Discuss

this question with a classmate. Choose a way to

summarize your discussion.

CHECK-IN

PROTECTING OURSELVESDisaster response organizations have some advice to offer. In case of volcanic eruption, people should leave the area immediately. The organizations also recommend having breathing protection, such as masks, and emergency supplies of food and water on hand. In case of an earthquake, people indoors should seek shelter, for example, behind a large piece of furniture or against an interior wall. People outdoors should stay in the open away from large trees, buildings, and power lines. They should not move away until the possibility of aftershocks has passed.

IMPROVED TECHNOLOGIES AND STRUCTURESImproved technologies, such as seismographs, are helping scientists predict earthquakes and volcanoes. There are about 4000 seismographs around the world, constantly recording the time and size of each quake.

When a seismograph records a series of small shocks in an area, scientists know that a plate boundary may be undergoing pressure at a particular location, which could mean that a large quake is coming.

As well, before a volcanic eruption occurs, magma moves into an area below the volcano. Sometimes, seismographs can alert scientists to these movements of magma. They may be able to predict a volcanic eruption.

No one has been able to design a structure that could survive a direct hit from a massive earthquake. But in places where earthquakes are common, laws require buildings to be more resistant to earthquake damage.

As a result, engineers are improving structures. They have developed new building materials that bend, instead of break, when shaken by shock waves. They have designed walls that contain braces to help them resist shaking and prevent collapse. Whole buildings have been designed with flexible bases to absorb shock waves. They remain still even when the ground is moving. Figure 1.24 shows an example of this kind of building.

FIGURE 1.24 The Transamerica Pyramid in San Francisco survived a large earthquake in 1989.

How does the design of this building make it earthquake-proof?

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